Method of producing zinc oxid.



H. H. HUGHES.

METHOD OF PRODUCING ZINC OXID.

APPLICATION FILED MAY27,1911.

EQQSQ, i Patented Jan. Q, 19l2.

m/ um BARRY H. HUGHES, or sr. Louis, Missouar.'

METHOD or 'raonucme zinc oxno.

noiaoea l Application filed May 27, 1911. Serial No. 629,912.

Specification of Letters Patent.

Patented Jan.. 9, 1l9f2.

To all 'whom 'it may concern: l

Be it known that I, HARRY H. HUGHES, a citizen of the United States, residing at St. Louis, Missouri, have invented a certain new and useful Improvement in Methods of Producing Zine OXid, of which the following is a full, clear, and exact description, such as will enable others skilled in the art to which it appertains to make rand use the same, reference being had to the accompanying drawings, forming part of this specification, in which- The figure is a longitudinal section taken vertically through the center of a simple form of apparatus particularly designed for practicing my improved method.

This invention relates to improvements in the method of treating sulfid and other ores of zinc for the production of zinc oXid or .what is commercially known as zinc white.

The principal object of my invention is the provision of a simple, easily practiced continuous method of treatin sulld and other ores of zinc so as to rapidly produce at little cost a zinc oXid, or zinc white.

Among the important features of my improved method is, first, the somple and economical elimination in a marketable form of the zinc contained in complex ores, which besides carrying zinc carry iron, copper, lead, silver, gold and other metals; second,

the feature of the continuous mechanical treatment of the ore; third, the feature of obtaining complete combustion of all the carbon used for heating and reduction in the furnace itself; and fourth, the conservation of the heat of the ore, as it passes from the roasting furnace into the rotary reduction cylinder, for by taking the heated ore direct from the roasting furnace and delivering said ore into the reduction cylinder it is a comparatively easy and inexpensive matter to obtain the degree of heat necessary within the reduction chamber to bring about the. oxidation necessary to produce zinc oxid.

Other features and objects of my invention will be apparent fromvthe following detailed description, wherein my improved method as practiced with the apparatus shown is fully set forth. It will be understood, however, that other forms of apparatus than the one herein shown and described l may be 'advantageously utilized for treating zinc ores for the production of zinc oxid.

In the particular form of apparatus illustrated, 1 designates an ordinary ore roasting furnace, and leading directly therefrom is a chute or spout 2, which is preferably inclosed by a layer 3 of non-heat conducting material. y

4 designates a housing of fire brick or analogous' material, which incloses a chamber 5, and leading therefrom is, a stack or outlet pipe 6. This outlet pipe or stack leads to suitable `collecting chambers or bag houses of ordinary design and used for collecting zinc oxid. v

7 designates an elongated cylinder referably lined with lire brick, which cyllnder is mounted for rotation on suitable roller bearings 8, and said vcylinder is slightly inclined so that material entering the upper end will gradually gravitate and discharge from the lower end as said cylinder is slowly 'Y rotated. The upper end of this cylinder 7 extends through one of the walls 'of the housing 4: and receives the discharge end of thespout or chute 2.` The lower end of the cylinder is preferably open as shown, although suitable means may be provided for partially closing said lower end to regulate the air supply into said cylinder.

9 designates a hydro-carbon supply pipe, j

the nozzle 10 of which is positioned in the open lower end of the cylinder 7, andD thus the flame resulting from the ignition of lthe liquid or gaseous hydro-carbon as it discharges from said nozzle is projected through the cylinder 7, thereby impinging directly upon the stream of ore passing through the cylinder.

In the treatment 'of sulid ore carrying Zinc, said ore is first roasted in the furnace l in order to drive oif the `sulfur in the usual manner and to accomplish this result it is necessary to develo a temperature of approximately 900 within the furnace 1. The ores freed from the sulfur gases pass into and through the spout or chute 2 and discharge therefrom into the upper end of the cylinder 7, which during the practicing of my improved method is slowly rotated. The upper portion of the chute or tube 2 is insulated against the radiation of heat,

and therefore,the ore discharging into the upper end of the cylinder 7 maintains approximately the same degree of heat that it was subjected to in the roasting furnace, viz: 9 00o C. The ignition of the hydrocarbon discharging from the nozzle- 10 in the lower end ofthe cylinder 7 brings the temperature up to a proximately 1300o C. within the cyllnder which heat is necessary for the proper reduction o f the ore to,

produce zinc white. This hydroLcaibon {iame acts as a reduction material and the air drawn into the cylinder by the suction produced by the hydrocarbon flame together with the carbon ioxid produced from the l combustion of the oil or gas causes a rekThe zinc white fumes roduced within the .I cylinder 7 pass rearward y therethrough and discharge therefrom into the chamber 5, and pass from thence into and through the stack or outlet 6 into suitable collecting chambers or bag houses wherein the zinc white is collected in the usual manner. The chute or spout 2is kept full of ore and thus the zinc white fumes are prevented from passing upwardly through the chute or spout and into the roasting furnace 1.

By my improved method of substituting the hydro-carbon Aflame for the solid carbon ordinarily used as a reducing agent, -and x the practically complete combustion of the gases within the rotating cylinder, the zinc oxid or zinc white escapes from the rotating cylinder and passes through the stack 6 to the collecting chamber uncontaminated by carbon, and therefore, said zinc oxid can be produced clean and white and practically pure. Y

Where zinc white lis produced by my improved method from oxid ore, silicates or carbonates the roasting furnace 1 can be dispensed with, inasmuch as it is not necessary to roast the oxid ores, silicates or carbonates. In some instances, with certain ades of ore it may be found advisable to mlx a small vamount of carbon with the ore, and which carbon acts as a reduction material.

By slightly inclining the cylinder and slowly rotating the same the material fed into the cylinder is continuously agitated as it passes therethrough, and by the time v said material passes from one end ofthe i cylinder to the other-4 practically all .of the metallic vapors have passed olf to be oxidized and converted into zinc oxid or zinc white, 66 which as heretofore described passes through i of oxid from complex `ores usually carrying:

gold, silver, iron, copper, lead and other metals, so as to render such complex ores available in the ordinary treatment for blast A furnaces, or such treatment as is usually given to this class of ores. The hydrocarbon flame from the burner in the lower end of the cylinder impinges directly upon the stream of roasted or oxidized ore as it passes downward through the rotating cylinder, and by the regulation of the air supply into the lower end of the cylinder and regulating the burner, the flame can be so manipulated as to burn the carbon in the oil or` gas (according to the form of fuel used) to carbon monoxid, CO.. This CO is an excellent reducer for zinc oxid and by taking up another atom of oxy en from the ZnO of the roasted ore the car n completes combustion by burning to carbon dioxid CO2. At the `same time the ZnO in the ore is reduced to metallic zinc, which is immediately CO2- to ZnO, or zinc white.

I claim:

1. The herein described continuous method of producing zinc oxid from sulfid and 2. The herein describdd continuous method of producing zinc oxid, consistingin initially applying heat to the zinc ore ,under treatment to'eliminate practically all of the volatilized and reoxidized by 'other sulfur bearing ore' consisting in roastsulfur from said ore, then delivering said i ore to andl passing it throu h a chamber heated solely by the combstlon of hydrocarbon lwithin the chamber, continuously agitating the ore while in the chamber, and introducing air into said chamber to reduce the zinc vapors to an oxid.

y 3. The herein described continuous method of producing zinc oxid'from zinc .ore from which the sulfur has been eliminatedk consstingin passing the heated zinc ore through 1n testimony whereof I' hereunto ax my a chamber heated solely by the combustion signature in the presence of two Witnesses, of hydrocarbon Within said chamber, conthis 25th day of May, 1911. Y

tinuously agtating said ore while passing HARRY H. HUGHES 5 through the chamber, and' introducing air Witnesses:

into said chamber reduce the zinc vapors M. P. SMITH,

to an oxid. B. S. Rm. 

